The objective of the proposed work is to elucidate the importance of membrane-related events such as depolarization and calcium transport in skeletal metabolism. Tissue culture techniques are empolyed to examine the effects of membrane-active agents (local anesthetics, anticonvulsants, inophores, calcium antagonists) on various parameters of skeletal demineralization and collagen synthesis. Demineralization will be quantitated by measuring the release of previously incorporated 45Ca from fetal rat long bones to medium; collagen synthesis will be quantitated by measuring the incorporation of (3H) proline into collagen and noncollagen protein in fetal rat calvaria. Various hormones (e.g., parathyroid hormone, calcitonin, insulin) will be utilized to increase/decrease demineralization and collagen formation; membrane-active drugs will be tested for their effects on hormonal-induced changes in these parameters. In addition, the effects of horomnes and membrane-active drugs on skeletal hyaluronic acid, cyclic AMP and cyclic GMP synthesis will be examined, in order to clarify the role of these intracellular products in skeletal metabolism. These studies will provide information as to the role of depolarization and calcium transport in the control of bone turnover.